Post by koganusan on Nov 13, 2017 6:21:14 GMT

I was about to post a challenge thread for a ship made primarily of biological or biologically producible materials, but I realized that many of the materials that would be needed to have any real shot at it aren't available. Some of the obvious standouts I'd like to see are limpet teeth, tooth enamel, chitin, keratin, sponge spicules, abalone shell, guanine crystal (found in shiny fish scales, parabolic mirrors in the eyes of scallops and a few other places and maybe usable for a laser mirror?), and bulk versions of biologically relevant minerals like argonite and magentite. This may be worth skimming to get a sense of what all is out there.

Post by koganusan on Nov 14, 2017 5:59:48 GMT

Here's a first shot at abalone nacre. Composition is approximated as aragonite, which makes up 95% of it by mass. No idea what the exact composition of the 5% protein is. The electrical properties, refractive index and roughness are taken from calcite. The "melting point" is the approximate temperature at which the organic layers decompose and the aragonite turns to calcite.Material Abalone NacreElements Ca C OElementCount 1 1 3IsABiomaterial trueDensity_kg__m3 2763YieldStrength_MPa 180UltimateTensileStrength_MPa 180YoungsModulus_GPa 70ShearModulus_GPa 35MeltingPoint_K 708SpecificHeat_J__kg_K 900ThermalConductivity_W__m_K .9ThermalExpansion__K 5.8e-5Resistivity_Ohm_m 2e12RelativePermittivity 8.1RefractiveIndex CalciteRoughnessCoefficient .9All together a pretty unexceptional ceramic, if not for the fact that a mollusk can make it at room temperature. A lot of what makes it nifty doesn't actually get modeled, it would seem.

Post by Fgdfgfthgr on Nov 15, 2017 23:59:35 GMT

One day, someone will make an alive ship. And it extracts its food from the atmosphere of gas giants, gets energy from electromagnetic wave and waves power of the winds in the atmosphere. Propellent itself through fission busts. Reproduce by a bio-factory. And shoot plasma like Bombardier beetle.Well, the origin of Space Whales.

Post by koganusan on Nov 17, 2017 0:24:32 GMT

One day, someone will make an alive ship. And it extracts its food from the atmosphere of gas giants, gets energy from electromagnetic wave and waves power of the winds in the atmosphere. Propellent itself through fission busts. Reproduce by a bio-factory. And shoot plasma like Bombardier beetle.Well, the origin of Space Whales.

That's probably going to have to wait on modding in more and better biomaterials for one thing. As is, restricting myself to biologically plausible materials, propellants and temperatures as much as possible, the best space whale I can build limps along on a 1Km/s-ish low thrust hydrogen peroxide chemical rocket and is armed only with similarly bad kinetic missiles that amount to a smaller version of itself. To do any better, it's going to take a decently moderate to high temperature, moderate to high strength non-porous material and a couple materials useful for things like thermocouples, radiators and guns, to say nothing of the possibility of lasers. Also, if we want to be really anal about it, an explosive or two and stats for one of the minerals some bacteria use to sequester uranium would both be nice to have.

I think the end goal should be something with enough delta-v to plausibly slowly spread through a system and most of the capabilities of standard ships being possible in some form, though presumably not all that good. Bonus points if it somehow ends up with a big honking laser or decent strategic missiles or something that could make it not worth messing with.